TinyShip Feature Development

Step-by-step guide for adding new features to a TinyShip project, following the monorepo architecture patterns.

Step 0: Scope the Feature

Ask the user to clarify:

1. What type? UI only / API only / full-stack
2. What does it do? Brief description of the feature
3. Does it need auth? Should it be protected?
4. Does it consume credits? If AI-related, should it charge credits?

Step 1: Shared Logic (libs/)

Put domain/business logic in libs/ — never duplicate it across apps.

Read the root AGENTS.md for the full feature checklist and libs/*/AGENTS.md for existing library patterns.

When to create a new lib vs extend existing:

• Payment-related → extend libs/payment/
• Auth-related → extend libs/auth/
• AI-related → extend libs/ai/
• New domain → create libs/your-domain/ with an AGENTS.md

Step 2: Configuration (config/)

If the feature needs configurable options:

1. Add a new config file config/yourFeature.ts or extend an existing one
2. Export it from config.ts
3. Add any new env vars to env.example with descriptions

Step 3: API Route

Create the API endpoint in the active app:

Next.js: apps/next-app/app/api/your-feature/route.ts

import { yourLogic } from '@libs/your-domain';

export async function POST(req: Request) {
  // Auth check, input validation, call shared logic, return response
}

Nuxt.js: apps/nuxt-app/server/api/your-feature.post.ts

import { yourLogic } from '@libs/your-domain';

export default defineEventHandler(async (event) => {
  // Auth check, input validation, call shared logic, return response
});

TanStack Start: Use createServerFn or traditional API route.

Step 4: Page/UI

Create the frontend page:

Next.js: apps/next-app/app/[lang]/your-feature/page.tsx Nuxt.js: apps/nuxt-app/pages/your-feature.vue TanStack Start: apps/tanstack-app/src/routes/[lang]/your-feature.tsx

Use shared React components from libs/react-shared/ (Next + TanStack).

Step 5: i18n

Add translation keys in both language files:

1. libs/i18n/locales/en.ts — English (source of truth)
2. libs/i18n/locales/zh-CN.ts — Chinese (mirror same structure)

// In en.ts
yourFeature: {
  title: 'Your Feature',
  description: 'Feature description',
  // ... all user-facing strings
}

Never hardcode user-facing strings in components.

Step 6: Auth & Permissions

If the feature requires authentication:

Next.js: Add route to middleware protection in apps/next-app/middleware.ts Nuxt.js: Configure in apps/nuxt-app/server/middleware/permissions.ts TanStack Start: Add beforeLoad guard in the route definition

For role-based access, use the CASL permissions system in libs/permissions/.

Step 7: Credits (if applicable)

If the feature consumes credits:

1. Define cost in config/credits.ts
2. Use creditService.consumeCredits() from libs/credits
3. Add transaction type code in libs/credits/utils.ts
4. Add credit description translations in libs/i18n/locales/

Step 8: Verify

# Typecheck
pnpm --filter @tinyship/next-app typecheck  # adjust for your app

# Build
pnpm --filter @tinyship/next-app build

Test the feature manually:

1. Navigate to the new page
2. Test the API endpoint
3. Verify auth protection works
4. Test i18n by switching languages

Reference Files in TinyShip Repo

• AGENTS.md — root feature checklist (the definitive reference)
• libs/*/AGENTS.md — per-library patterns and architecture
• .cursor/rules/project-structure.mdc — monorepo layout guide
• libs/i18n/AGENTS.md — i18n conventions
• libs/permissions/AGENTS.md — permission system guide